The invention relates generally to self-propelled lawn mowers and more particularly to multi-speed transmissions for self-propelled lawn mowers having forward and reverse drives and to means for shifting such transmissions.
Self-propelled lawn mowers typically are driven by a transmission connected to the cutter blade drive shaft. The transmission generally provides for rotation of the mower drive shaft in only one direction such that the lawn mower is self-propelled in only one direction. Additionally, common methods of providing a self-propel system for a lawn mower require shifting of the transmission with the transmission under load and the power being directly connected to the drive wheels during shifting. Such arrangements cause loading of the transmission components and drive shaft during shifting.
U.S. patent application Ser. No. 872,638 filed Jan. 26, 1978 by Schlapper and assigned to the assignee of the present invention discloses a transmission for a self-propelled power mower including a drive shaft having drive means on its ends, the drive means being engageable with drive wheels to thereby drive the drive wheels of the mower. The drive means include a low-speed drive member mounted on the drive shaft for common rotation therewith and for engaging a drive wheel and a high-speed drive member having an outer diameter greater than the diameter of the low-speed drive member. The high-speed drive member is splined on the low-speed drive member and is selectively and alternatively moved into engagement with the drive wheel.
U.S. Pat. No. 2,947,132, issued Aug. 2, 1960 to Shaw discloses a transmission for a power mower or the like including a drive shaft which is drivingly connected to a prime mover and a pair of the mower wheels selectively movable into frictional engagement with the drive shaft to drive the mower.
U.S. Pat. No. 2,962,854 issued Dec. 6, 1960 to Jepson discloses a two-speed drive gear having concentric rings of gear teeth and a driven gear which is connected to a wheel-engageable drive shaft and can be moved axially to mesh with either of the drive gear rings for varying the mower speed.
U.S. Pat. No. 2,736,389, issued Feb. 28, 1956, U.S. Pat. No. 3,433,002, issued Mar. 18, 1969 and U.S. Pat. No. 3,035,385, issued May 22, 1962 each disclose another alternative means for driving a self-propelled lawn mower.